Fire alarm



Dec. 14, 1954 D. M. JACOBY 2,696,798

FIRE ALARM Filed March 1, 1952 ATTORNEY.

United States Patent FIRE ALARM David M. Jacoby, .Doylestown, Pa.

Application March 1, 1952, Serial No. 274,389 b 4 Claims. Cl. 116-106) V The present invention relates to audible alarms and particularly to fire alarms or heat-sensitive alarms.

An object of the present invention is to provide a self-contained fire alarm.

Another object of the present invention is to provide a unitary fire alarm constructed and arranged to emit an audible signal to indicate temperature-increase of the surrounding atmosphere.

Other objects will be apparent by reference to the appended specification, claims and drawings.

For the purpose of illustrating the invention, there is shown in the accompanying drawings one form thereof which is at present preferred, although it is to be understood that the various instrumentalities of which the invention consists can be variously arranged and organized and that the invention is not limited to the precise arrangements and organizations of the instrumentalities as herein shown and described.

In the drawings wherein like reference characters indicate like parts:

Figure 1 represents a perspective view of a room wherein two of the alarms of the present invention are operatively mounted; one on the wall and one on the ceiling.

Figure 2 represents a perspective view, partly in section, of an alarm which is one embodiment of the present invention.

Figure 3 represents a fragmentary vertical cross-sectional view taken generally on line 33 of Figure 2.

Figure 4 represents a fragmentary cross-sectional view, on an enlarged scale, of the discharge nozzle and juxtaposed Whistle shown in Figure 3.

Figure 5 represents a vertical cross-sectional view of the valve-nozzle of the embodiment of the alarm shown in Figure 2.

The alarm which is one embodiment of the present invention includes a vessel 11, capable of withstanding excessive pressures from within, and having a threaded aperture 12 at one end 13 with a valve-nozzle 14 screW-threadedly secured, in an air-tight manner, in an aperture 12.

The valve-nozzle 14 has a bore 15 and a counter-bore 16 and a ball-check in the counter-bore 16; said ballcheck including the ball 17 urged by the spring 18 against the seat 19 surrounding the bore 15. On the opposite side of the seat 19 from the ball 17 is a threaded counter-bore 20 in which a plug or cap 21 may be secured. A sleeve 22 is press-fitted at the outer end of the counter-bore 16 to retain the spring 18 and ball 17 in the counter-bore 16.

A transverse port 23 is formed in the valve-nozzle 14 at an angle to and intersecting the counter-bore 16 intermediate the ball 17 and the sleeve 22.

The outer end of the port 23 is sealed with a fusible low-melting-point alloy (which may include bismuth, tin and/or cadmium and which may be of the type known as Belmont #140). This loW-melting-point alloy forms a plug 24 at the outer end of the port 23 as long as the temperature surrounding said plug does not exseed a pre-determined amount, as, for instance, 140 F.

The nozzle-valve 14, when secured to the threaded aperture 12, provides means for filling the vessel 11. The plug 21 is removed from the threaded counter-bore 20 and a supply-conduit connected thereto and a gas under pressure is admitted through the valve 14 (depressing the ball 17 against the spring 18). When the supplyconduit is disconnected from the threaded counter-bore 20, the gas, under pressure, is retained within the vessel Patented Dec. 14, 1954 11 because the ball 17 seats securely against the valveseat 19. In addition, the plug 21 may be sealed in the counterbore 20 to prevent accidental leakage of the gas from the vessel 11.

melts the vessel contents expand, as a gas, through the port 23 and the discharge of the gas through the port 23 continues for a relatively long period of time.

An audible sounding device such as the whistle 25 is operatively secured adjacent the vessel 11, .as by the support 26, in alignment with the port 23 of the nozzle '14 so a gaseous discharge from the port 23 is directed towardsand against the whistle25 to operate said Whistle.

It is to be understood that the sounding device need not be a whistle but may he an air horn or the like and, moreover, it is not necessary that the audible signaling means he supported in spaced relationship to the discharge end of the port 23 but may, if desired, be directly connected thereto.

The operatively interconnected vessel, nozzle and signaling means may be suitably supported within and concealed by a heat-collector or heat-absorbing shield 27- said shield having a plurality of vents or apertures 28 to permit air-circulation within said shield. In addition, a heat-conductor or bar 29 may be operatively secured intermediate the shield 27 and the nozzle 14-said conductor having a finger-like end 30 for engagement within a groove 31 in the nozzle 14 whereby to hold the conductor 29 in intimate contact with the nozzle 14 so as to conduct heat from said shield 27 to the nozzle 14 and to the fusible plug 24 therein so that the nozzle 14 and the shield 27 will, at all times, be at the same temperature, and so that any rise in temperature in the vicinity of the alarm or any rise in temperature impinging upon the shield 27 either by contact with the surrounding air or by radiation, which therefore raises the temperature of the shield, will be quickly conveyed to the fusible-plug 24.

The shield 27 may include a pair of in-turned flanges 32 having stop-members 33 at one end; said flanges being constructed and arranged to engage the shoulder portions 34 of a mounting plate 35. The mounting plate 35 may be mounted on any convenient or suitable surface such as a wall or ceiling or the like whereupon the vessel-containing shield 27 may be secured to the mounting plate 35 by sliding the flanges 32 behind the shoulders 34 until the stop-members 33 engage the ends of the shoulders 34.

The operation of the invention is as follows. After the alarm has been suitably mounted, as illustrated in Figure 1, it will remain inoperative as long as the temperature of the surrounding atmosphere (or surface) does not exceed the temperature at which the plug 24 fuses, as, for instance, F. When the temperature of the surrounding atmosphere or surfaces reaches or exceeds 140 F. the heat will be transmitted through the heat-absorbing or heat-collecting shield 27 and conductor 29 to the nozzle 14 and plug 24 whereupon the plug will melt and the port 23 will be opened. Thereupon the gas in the vessel 11 will be discharged through the port 23 against the sounding means (whistle 25) whereby to cause an audible signal and warn of the increase of temperature of the surrounding atmosphere and/or surfaces. The sounding of the alarm will continue for a period long enough to attract attention thereto as, for instance, five minutes.

After the alarm has once been operated and the gas within the vessel 11 discharged, the alarm may be used over and over again merely by removing the shield 27 and vessel 11 from the mounting bracket 35, removing the vessel 11 from the shield 27, re-plugging the port 23 with more fusible alloy, and recharging the vessel through the va ve 14.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

What is claimed as new and desired to be protected by Letters Patent is the following:

1. A unitary fire alarm including a closed vessel containing easily-liquifiable non-inflammable gas under pressure, a nozzle-valve in said vessel and a discharge-port in said nozzle-valve, said discharge port being substantially smaller than said vessel, a fusible plug in said discharge-port and signaling means in operative juxtaposition to said port.

2. A unitary fire alarm including a closed vessel containing easily-liquifiable non-inflammable gas under pressure, an aperture at one end of said vessel, said aperture being substantially smaller than said vessel, a fusible plug in said aperture and signaling means in operative juxtaposition to said aperture, and a cover for said vessel and said signaling means.

3. A unitary fire alarm including a closed vessel containing easily-liquifiable non-inflammable gas under pressure, an aperture at one end of said vessel, said aperture being substantially smaller than said vessel, 21 fusible plug in said aperture and signaling means in operative juxtaposition to said aperture, and a cover for said vessel and said signaling means, with a heat-conductor operatively interconnecting said cover and said plug.

4. A unitary fire alarm including a closed vessel containing easily-liquifiable non-inflammable gas under pressure, a heat-absorbing shield therefor, an aperture at one end of said vessel, said aperture being substantially smaller than said vessel, a fusible plug in said aperture, signaling means in operative juxtaposition to said aperture, and heat-conducting means operatively connecting said heat-absorbing shield and said fusible plug.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 754,847 Clark Mar. 15, 1904 2,034,179 Franklin Mar. 17, 1936 2,211,142 Loudon Aug. 13, 1940 2,483,657 Messick Oct. 4, 1949 2,498,193 Anglo Feb. 21, 1950 

